It's much to hard to decide an all-time favorite, but certainly Absolutely Fabulous and My So Called Life were two shows that I loved, and which I can remember everything about.
Some more of my all-time favorites:
Little House on the Prairie
The Dukes of Hazzard
You Can't Do That On Television
The Smurfs
Scooby-Doo
Keeping Up Appearances
Are You Being Served
The Benny Hill Show
Red Dwarf
The Flintstones
The Jetsons
The Simpsons
Our House
Saved By The Bell
Star Trek: The Next Generation
Mama's Family
The Facts of Life
The Love Boat
Gimme a Break
Mr Wizard's World
3.. 2.. 1.. Contact
What's Happening
The Jeffersons
Family Matters
The New Leave it to Beaver
All That
Ghostwriter
Clarissa Explains it All
Reading Rainbow
The Littles
Fraggle Rock
Hey Dude
Sesame Street
Rugrats
Salute Your Shorts
Pee Wee's Playhouse
Beverly Hills, 90210
In Living Color
Six Feet Under
The Real World (The first season, and the L.A. and Miami seasons esp.)
Family Plots
Mythbusters
Crank Yankers
Reno 911
Chapelle's Show
There are also two Spanish-language shows which I count among my favorites, they are El Chapulin Colorado and Chespirito.
My favorite show right now is Little People, Big World.